King Carter died in 1732, and Landon inherited a fraction of his father's estate. Shortly thereafter, he married Elizabeth Wormeley, daughter of John Wormeley, who died in 1740. In 1742 Landon married Maria Byrd, daughter of William Byrd II, who died in 1744. He married his third wife, Elizabeth Beale, in 1746.
Shortly after his first marriage, Landon settled on lands he had inherited in Richmond County. His mansion house, Sabine Hall, which he built about 1734, stood at the heart of his plantation there. At his death he left to his heirs 50,000 acres (200 km²) of land and as many as 500 slaves.